Such a device has already been known (GB-PS No. 1,460,711). In this device, a nozzle head is deflected to oscillate by means of a drive mechanism transversely to the direction of the jet of pressure medium ejected from a nozzle orifice. The drive mechanisms used therein are ultrasonic transducers, electro-mechanical transducers and also mechanically or hydraulically driven mechanisms. The nozzle had itself is supported in bearings so that it is either movable linearly or pivotable about a bearing journal. It has been found, however, that this kind of bearing is subject to rapid wear when operating with oscillatory movements of relatively high frequency, as is recommended for efficient cutting.
The same problems arise with a further known device (GB-PS No. 2,027,776) in which likewise a nozzle head including a cam is reciprocable on a linear guide path of a bearing unless a bearing journal is also used for bearing purposes. This device is used for knocking concrete off reinforcement system or for removing a flooring by means of a liquid jet.
It is furthermore known (DE-OS No. 3,516,572) to provide a nozzle head, which is mounted on a flexible high-pressure hose, with a plurality of nozzles screwed into the end face of the nozzle head. A central nozzle extends in axial direction of the nozzle head while on either side of the central nozzle two further nozzles are provided with their nozzle axes inclined relative to the axis of the nozzle head. This nozzle head has already been found satisfactory for rock cutting.